Structural study of fluoro-tetraphenylporphyrins relating to large variability in solubilities of the para-F-TPP, ortho-F-TPP and meta-F-TPP

We present the X-ray structures of the crystals of the ortho-, meta-, and para-F-tetraphenylporphyrins crystallized from different solvents to shed light on the differential solubility of these three isomers. The meta-F-TPP is 4300 times more soluble than the para-F-TPP isomer in chloroform. It is shown that the packing of the porphyrins in the crystal is not a key issue in this solubility difference. However, we discovered a large difference in the temperature factors of the phenyls and Fs in the various isomers and this gives us insight into the solubility differences.